A low-protein diet requires you to restrict the amount of protein you consume, typically so that it constitutes 4–8% of your daily calories.

This translates to somewhere between 20–50 grams of protein per day, depending on how many calories you consume.

For comparison, the average person is generally recommended to get at least 10–15% of their daily calories from protein. This amount may increase for athletes, older adults and those with certain health problems (1).

Protein is vital to health, but reducing protein intake can be therapeutic for people with specific conditions.

In particular, low-protein diets may benefit those with decreased kidney or liver function.

They may also be necessary for those with disorders that affect protein metabolism, such as homocystinuria and phenylketonuria.

However, going on a low-protein diet requires careful planning to prevent health issues and nutritional deficiencies.

Additionally, there are other risks and potential drawbacks you should consider before beginning a low-protein diet.

Summary A low-protein diet generally reduces protein intake to make up around 4–8% of your daily calories. It may be beneficial for those with certain health conditions, but there are also some risks to consider.

The benefits of a low-protein diet mostly apply to people with specific health conditions or diseases, rather than those who are generally healthy.

Excess protein is typically broken down by the liver, producing a waste product called urea, which is excreted by the kidneys (2).

Decreasing protein intake can ease the workload of the liver and kidneys, which can be beneficial for people with liver disease or impaired kidney function.

This helps improve protein metabolism and prevents a buildup of urea in the bloodstream.

Having high levels of urea in the blood causes symptoms like fatigue, loss of appetite, weight loss and changes in mental status (3).

It may also be associated with a higher risk of type 2 diabetes and death in those with heart failure (4, 5, 6).

Reducing protein intake is also necessary for those with genetic disorders that affect protein metabolism, such as homocystinuria and phenylketonuria.

These disorders impair the breakdown of specific amino acids, so reducing protein intake can help minimize symptoms (7, 8).

Some research has also found that low-protein diets may be associated with several health benefits for the general population.

According to one review, restricted protein intake in middle-aged adults was associated with increased life expectancy and reduced risks of chronic conditions like cancer, heart disease and diabetes (9).

However, more studies are still needed to evaluate the potential long-term benefits of protein restriction in healthy adults.

Summary Reducing protein intake can be beneficial for those with conditions like liver and kidney disease, phenylketonuria and homocystinuria. One review also reported that it may increase longevity and reduce the risk of chronic disease.

However, on a low-protein diet, you may need to cut that amount in half and stick to a 2-ounce (57-gram) serving to keep your protein intake in check.

High-Protein Foods to Limit or Avoid

Meats like chicken, turkey, beef and pork

Fish and shellfish

Eggs

Legumes, including beans, peas and lentils

Dairy products like milk, cheese and yogurt

Soy products like tofu, tempeh and natto

Nuts like walnuts, almonds and pistachios

Seeds like chia seeds, flaxseeds and hemp seeds

Summary If you’re on a low-protein diet, limit high-protein foods like meat, fish, eggs, legumes, dairy products, soy, nuts and seeds. At the same time, increase your intake of healthy low-protein foods like fruits and vegetables.

If you are living with a condition that affects your liver or kidneys or interferes with protein metabolism, a low-protein diet may be necessary to help reduce your symptoms.

However, for healthy individuals, there's limited evidence that it has any health benefits.

Also, a low-protein diet requires careful planning to minimize potential health risks and nutritional deficiencies. It should only be done under medical supervision.

It’s crucial to consult a doctor or dietitian before starting a low-protein diet. Not only can they help determine if it’s a good option for you, but they can also provide guidance to ensure your diet is still healthy and well-rounded.